JP2010181468A5

JP2010181468A5 -

Info

Publication number: JP2010181468A5
Application number: JP2009022719A
Authority: JP
Filing date: 2009-02-03
Publication date: 2012-03-22
Anticipated expiration: 2029-02-03

Description

本発明は、連続画像形成の最初から最後まで、記録材の外側への引張り条件が揃った加熱処理が行われて、記録材しわや端部の画像乱れが発生しにくい画像形成装置を提供することを目的としている。 The present invention provides an image forming apparatus in which a heat treatment with uniform tension conditions to the outside of a recording material is performed from the beginning to the end of continuous image formation, and the recording material is less likely to cause wrinkles and image disturbance at the edges. The purpose is that.

本発明の画像形成装置は、記録材上の画像を加熱するための加熱ローラと、前記加熱ローラとの間で記録材を挟持搬送するニップ部を形成するための加圧ローラと、記録材を前記ニップ部に向けて搬送する搬送手段と、前記加熱ローラと前記加圧ローラを接離させる接離手段と、前記加圧ローラの長手方向の温度分布を調整する温度調整手段と、前記搬送手段による記録材の搬送タイミングを制御する搬送制御手段とを有するものである。そして、前記接離手段により前記加熱ローラと前記加圧ローラを離間させた状態で前記温度調整手段により前記加圧ローラの長手方向端部の温度が長手方向中央部の温度以上となるように調整する立ち上げモードを有し、所定の坪量よりも小さい複数の記録材に連続して画像加熱処理を行うとき、前記立ち上げモードを経て前記加圧ローラの長手方向端部の温度が長手方向中央部よりも所定温度高くなった時点で最初の記録材が前記ニップ部に到達するように前記搬送制御手段により記録材の搬送タイミングを制御するとともに前記ニップ部での画像加熱処理が開始されるように構成している。 An image forming apparatus of the present invention includes a heating roller for heating an image on a recording material, a pressure roller for forming a nip portion that sandwiches and conveys the recording material between the heating roller, and a recording material. Conveying means for conveying toward the nip portion; contacting / separating means for contacting and separating the heating roller and the pressure roller; temperature adjusting means for adjusting a temperature distribution in the longitudinal direction of the pressure roller; and the conveying means And a conveyance control means for controlling the conveyance timing of the recording material . Then, with the heating roller and the pressure roller separated by the contact / separation means, the temperature adjustment means adjusts the temperature of the longitudinal end of the pressure roller to be equal to or higher than the temperature of the longitudinal center. When the image heating process is continuously performed on a plurality of recording materials having a start-up mode that is smaller than a predetermined basis weight, the temperature of the end portion in the longitudinal direction of the pressure roller passes through the start-up mode in the longitudinal direction. The conveyance control means controls the conveyance timing of the recording material so that the first recording material reaches the nip portion when the temperature becomes higher than the central portion, and the image heating process at the nip portion is started. It is configured as follows .

加熱ローラの一例である定着ローラ２と加圧ローラの一例である加圧ローラ３との間に定着ニップ部Ｎを形成して記録材を挟持搬送する。 A fixing nip portion N is formed between a fixing roller 2 as an example of a heating roller and a pressure roller 3 as an example of a pressure roller, and the recording material is nipped and conveyed.

温度調整回路６１は、定着中央部温度センサ１７と定着端部温度センサ１８の出力に応じて定着中央部加熱ヒータ６と定着端部加熱ヒータ７を制御して、定着ローラ２を適正な温度に維持するように温度制御する。図４に示すように、定着中央部温度センサ１７は、定着ローラ２の長手方向中央部の表面温度を非接触に検知する非接触タイプである。定着端部温度センサ１８は、回転する定着ローラ２の長手方向端部に摺擦して表面温度を検知する接触タイプである。 The temperature adjustment circuit 61 controls the fixing center portion heater 6 and the fixing end portion heater 7 in accordance with the outputs of the fixing center portion temperature sensor 17 and the fixing end portion temperature sensor 18 to bring the fixing roller 2 to an appropriate temperature. Control the temperature to maintain. As shown in FIG. 4, the fixing central portion temperature sensor 17 is a non-contact type that detects the surface temperature of the central portion in the longitudinal direction of the fixing roller 2 in a non-contact manner. Fixing end temperature sensor 18 is a contact type for detecting the surface temperature by rubbing in the longitudinal direction end portion of the fixing roller 2 to rotation.

図４に示すように、ローラの長手方向の中央部の温度を検知する温度検知手段の一例である加圧中央部温度センサ１９は、加圧ローラ３の長手方向中央部の表面温度を非接触に検知する非接触タイプである。 As shown in FIG. 4, the pressure center portion temperature sensor 19 is an example of a temperature detecting means for detecting the temperature of the longitudinal center portion of the roller is a non-contact surface temperature of the central portion in the longitudinal direction of the pressure roller 3 Non-contact type that detects the

図２に示すように、加圧ローラ３は、定着装置１の加圧機構８ａに固定された軸受１１によって、両端を回転自在に軸支されている。加圧機構８ａは、定着ローラ２に対して加圧ローラ３を接離可能に支持するとともに、定着ローラ２に対する加圧ローラ３の圧接力を複数段階に変更可能である。 As shown in FIG. 2, the pressure roller 3 is pivotally supported at both ends by a bearing 11 fixed to the pressure mechanism 8 a of the fixing device 1. The pressure mechanism 8 a supports the pressure roller 3 so as to be able to contact and separate from the fixing roller 2 and can change the pressure contact force of the pressure roller 3 to the fixing roller 2 in a plurality of stages.

Claims

A heating roller for heating the image on the recording material;
A pressure roller for forming a nip portion for nipping and conveying the recording material with the heating roller;
Conveying means for conveying the recording material toward the nip portion;
Contact / separation means for contacting and separating the heating roller and the pressure roller;
Temperature adjusting means for adjusting the temperature distribution in the longitudinal direction of the pressure roller;
An image forming apparatus comprising: a conveyance control unit that controls conveyance timing of the recording material by the conveyance unit ;
In the state where the heating roller and the pressure roller are separated from each other by the contact / separation unit, the temperature adjustment unit adjusts the temperature of the end portion in the longitudinal direction of the pressure roller to be equal to or higher than the temperature of the central portion in the longitudinal direction. Up mode ,
When continuously performing image heating processing on a plurality of recording materials having a basis weight smaller than a predetermined basis weight, the temperature at the longitudinal end portion of the pressure roller becomes higher than the central portion in the longitudinal direction through the start-up mode. The conveyance control means controls the conveyance timing of the recording material so that the first recording material reaches the nip portion at the time, and the image heating processing at the nip portion is started. Image forming apparatus.

When the image heating process is continuously performed on a plurality of recording materials smaller than a predetermined basis weight, the diameter of the longitudinal end portion of the pressure roller becomes larger than the central portion in the longitudinal direction through the start-up mode. first image of claim 1, recording material, characterized in that the image heating process in the nip is started and controls the conveyance timing of the recording material by said conveyance control means to reach the nip portion in Forming equipment.

When continuously performing image heating processing on a plurality of recording materials larger than a predetermined basis weight, the temperature of the pressure roller is raised by the raising mode, and the longitudinal ends and the longitudinal direction of the pressure roller 3. The image forming apparatus according to claim 1, wherein an image heating process for the first recording material is started when the temperature of the heating roller reaches a predetermined temperature regardless of a temperature difference in the central portion .

The temperature adjusting means heats a longitudinal end of the first heater that has a higher ability to heat the longitudinal central portion than the longitudinal end of the pressure roller and a longitudinal central portion of the pressure roller. A second heater that has a high ability to perform, and a fan that selectively cools the longitudinal central portion of the pressure roller,
In the start-up mode, the temperature adjusting means adjusts the temperature of the end portion in the longitudinal direction of the pressure roller to be equal to or higher than the temperature of the central portion in the longitudinal direction by the second heater and the fan. The image forming apparatus according to claim 1 .

5. The image forming apparatus according to claim 1, further comprising an operation unit that allows an operator to specify a temperature difference between a longitudinal end portion and a longitudinal center portion of the pressure roller in the start-up mode. apparatus.

6. The image forming apparatus according to claim 1, further comprising a belt stretched by the heating roller and capable of contacting a recording material at the nip portion .

The image forming apparatus according to claim 1, further comprising a belt that is stretched by the pressure roller and that can contact the recording material at the nip .

A heating roller for heating the image surface of the recording material;
A pressure roller that forms a nip portion of the recording material in contact with the heating roller;
Contact / separation means for contacting / separating the heating roller and the pressure roller;
Heating means for heating the entire pressure roller in a state where the pressure roller is separated by the contact / separation means;
A cooling device that cools the central portion of the pressure roller in the longitudinal direction from the end portion in a state where the pressure roller is separated by the contact / separation means,
The image forming apparatus, wherein the cooling device performs a cooling operation before the first recording material is conveyed to the nip portion and stops the cooling operation.